Dr Carducci is nearing completion of a Phase I clinical and pharmacologic evaluation of oral PB. Patients with refractory solid tumors are placed on a three times daily schedule with escalating doses of the PB. The objectives of the study are to determine the maximum tolerated dose of sodium PB on this schedule. A total of 17 patients have been treated (10 advanced prostate cancer (CA), 3 renal cell CA, 2 breast CA, 1 thyroid CA, 1 colon CA). Dose escalation continues through 45g/day. Compliance has been excellent, despite the oral formulation, with patients ingesting 16 - 32 375mg tablets 3X a day. Pharmacokinetics were obtained on the GCRC after equivalent oral and IV doses prior to chronic dosing.